1. Field of the Invention
The present invention relates to an anti-corrosion structure for a wire connecting portion.
2. Description of the Related Art
In recent years, aluminum wires have been used for weight saving and other purposes also in the field of automotive wiring harnesses and the like. An aluminum wire is, for example, structured by covering a core formed by twisting a plurality of aluminum strands with a coating. In the case of forming a wiring harness, the aluminum wire is connected to a wire connecting portion of a terminal. This wire connecting portion is specifically composed of a wire barrel portion to be crimped and connected to an end of the core exposed by stripping the coating at an end of the aluminum wire and an insulation barrel portion to be crimped and connected to an end of the remaining coating.
In electrically conductively connecting a wire to a terminal, if a core of the wire and the terminal are made of different types of metals, particularly if moisture is present in a contact part of the both, electrolytic corrosion is known to occur in which the both metals are dissolved in the form of ions into water and corrosion progresses by an electrochemical reaction. Since the terminal is generally made of copper alloy in view of a problem in strength and the like, electrolytic corrosion is certainly a problem if the aluminum wire is used as described above.
Accordingly, in a terminal disclosed in Japanese Unexamined Patent Publication No. 2003-297447 below, electrolytic corrosion is prevented by sealing a wire connecting portion by a sealing resin (anticorrosive) made of silicone rubber, chelating agent and the like. However, since such a sealing resin entirely covers the wire connecting portion, the wire connecting portion is formed to be one size larger. Thus, a stepped part is formed on the terminal to avoid the interference of the sealing resin with a housing, into which this terminal is to be mounted, and the interference of the sealing resin and the housing is avoided by this stepped part.
However, in the above configuration, the housing is open upward and the wire connecting portion can be arranged while being displaced upward, but the sealing resin interferes with the inner wall of a through hole provided in the housing if the wire connecting portion is displaced upward in the case of accommodating the terminal into the through hole. On the other hand, even if a clearance between the inner wall of the through hole and the sealing resin is enlarged by carving the inner wall of the through hole, there is a limit in terms of securing the strength of the housing.